COA ACTUAL TEST 3 - ADVANCED
OPHTHALMIC ASSISTING 2026/2027
QUESTIONS AND ANSWERS
1. Which of the following conditions is characterized by a significant difference in the image
size perceived by each eye?
A. Anisometropia
B. Amblyopia
C. Aniseikonia
D. Aphakia
Answer: C
Conceptual Explanation: Aniseikonia is a condition where the brain perceives the image
from one eye as a different size or shape than the image from the other eye, often caused by
high anisometropia.
2. A prism diopter is defined as a prism that deflects a ray of light by how many centimeters
at a distance of one meter?
A. 0.5 cm
,B. 2.0 cm
C. 1.0 cm
D. 10.0 cm
Answer: C
Conceptual Explanation: One prism diopter (PD) is the power of a prism that displaces a
light beam by 1 cm on a flat surface held 1 meter away.
3. During a Humphrey Visual Field test, a ‘False Positive’ result indicates that the patient:
A. Did not respond to a stimulus that was clearly above the threshold
B. Suffered from a localized scotoma
C. Looked away from the fixation target
D. Responded to a stimulus when no light was actually presented
Answer: D
Conceptual Explanation: A False Positive occurs when a patient triggers the response
button (‘trigger happy’) without a light stimulus being presented, indicating poor
reliability.
4. Which layer of the cornea is responsible for maintaining deturgescence via an active
pumping mechanism?
A. Endothelium
B. Bowman’s layer
, C. Stroma
D. Epithelium
Answer: A
Conceptual Explanation: The endothelium contains metabolic pumps that regulate the
water content (deturgescence) of the corneal stroma to maintain transparency.
5. Calculate the focal length of a +5.00 D lens.
A. 20 cm
B. 5 cm
C. 50 cm
D. 10 cm
Answer: A
Conceptual Explanation: Focal length (f) = 1/D. For +5.00 D, f = 1/5 = 0.2 meters, which is
20 cm.
6. Which ocular muscle is primarily responsible for depressing the eye when it is in an
adducted position?
A. Inferior Rectus
B. Inferior Oblique
C. Superior Oblique
OPHTHALMIC ASSISTING 2026/2027
QUESTIONS AND ANSWERS
1. Which of the following conditions is characterized by a significant difference in the image
size perceived by each eye?
A. Anisometropia
B. Amblyopia
C. Aniseikonia
D. Aphakia
Answer: C
Conceptual Explanation: Aniseikonia is a condition where the brain perceives the image
from one eye as a different size or shape than the image from the other eye, often caused by
high anisometropia.
2. A prism diopter is defined as a prism that deflects a ray of light by how many centimeters
at a distance of one meter?
A. 0.5 cm
,B. 2.0 cm
C. 1.0 cm
D. 10.0 cm
Answer: C
Conceptual Explanation: One prism diopter (PD) is the power of a prism that displaces a
light beam by 1 cm on a flat surface held 1 meter away.
3. During a Humphrey Visual Field test, a ‘False Positive’ result indicates that the patient:
A. Did not respond to a stimulus that was clearly above the threshold
B. Suffered from a localized scotoma
C. Looked away from the fixation target
D. Responded to a stimulus when no light was actually presented
Answer: D
Conceptual Explanation: A False Positive occurs when a patient triggers the response
button (‘trigger happy’) without a light stimulus being presented, indicating poor
reliability.
4. Which layer of the cornea is responsible for maintaining deturgescence via an active
pumping mechanism?
A. Endothelium
B. Bowman’s layer
, C. Stroma
D. Epithelium
Answer: A
Conceptual Explanation: The endothelium contains metabolic pumps that regulate the
water content (deturgescence) of the corneal stroma to maintain transparency.
5. Calculate the focal length of a +5.00 D lens.
A. 20 cm
B. 5 cm
C. 50 cm
D. 10 cm
Answer: A
Conceptual Explanation: Focal length (f) = 1/D. For +5.00 D, f = 1/5 = 0.2 meters, which is
20 cm.
6. Which ocular muscle is primarily responsible for depressing the eye when it is in an
adducted position?
A. Inferior Rectus
B. Inferior Oblique
C. Superior Oblique
